1. Field of the Invention
This invention relates to a golf ball having the advantages of a straight long-lasting trajectory, minimized windage, and added run like the small-size ball.
2. Prior Art
Golf is the game for players to compete using their skill fairly. Many rules have been prescribed in order to ensure the equality of play. Inter alia, strict specifications have been set forth for golf balls because individual players are allowed to select balls for play using their own responsibility.
With respect to golf balls, particularly authorized balls for professional tournaments, specifications on the weight, diameter, spherical symmetry, initial velocity and overall distance are set forth in the worldwide accepted Rules of Golf as approved by the United States Golf Association and the Royal and Ancient Golf Club of St. Andrews.
In the past, there were two rules regarding the diameter and weight of golf balls, that is, small-size balls and large-size balls. In 1920, the R&A set forth the rule of small-size ball specifying a weight of not greater than 1.62 ounces (45.93 g) and a diameter of not less than 1.62 inches (41.15 mm). In 1931, USGA set forth the rule of large-size ball specifying a weight of not greater than 1.62 ounces (45.93 g) and a diameter of not less than 1.68 inches (42.67 mm). The two rules were used for decades. In a harmonizing process, the R&A amended the rule in 1990 to change the ball diameter from "not less than 41.15 mm" (small-size ball) to "not less than 42.67 mm" (large-size ball). In Japan too, the use of large-size balls has been the rule in men's professional tournaments since 1977. Nowadays large-size balls are commonly used.
As compared with the small-size ball, the large-size ball has the advantages of afloat movement on the grass, easy approach shots and easy recovery shots from the rough, and promoted rolling upon putting. Inversely, the large-size ball has the disadvantages that when hit against the wind, the ball gains a higher trajectory and a greater fall angle, resulting in a reduced run and flight distance, and the path is readily curved.
There is a desire to have a golf ball which satisfies not only the specifications of the large-size ball, but also the requirements of a straight long-lasting trajectory, minimized windage, and added run like the small-size ball.